Abstract:

An auxiliary exercise equipment comprises a footrest for supporting a foot
of a user. The footrest is configured so that a part of the footrest
relatively retreats from a remaining part of the footrest and thereby is
made apart from the foot while the remaining part of the footrest
supports the foot.

Claims:

1. An auxiliary exercise equipment, comprising a footrest for supporting a
foot of a user,wherein the footrest is configured so that a part of the
footrest relatively retreats from a remaining pan of the footrest and
thereby is made apart from the foot while the remaining pan of the
footrest supports the foot.

2. The auxiliary exercise equipment as claimed in claim 1, wherein the
footrest comprises a plurality of members,wherein the footrest is
configured so that at least one of the plurality of members is bent with
respect to a remaining member(s) of the plurality of members and thereby
is made apart from the user's foot.

3. The auxiliary exercise equipment as claimed in claim 2, wherein the
plurality of members of the footrest are separately arranged back and
forth.

4. The auxiliary exercise equipment as claimed in claim 3, wherein the
plurality of members of the footrest are a front half and a back
half,wherein the footrest is configured so that the front half is bent
downward with respect to the back half.

5. The auxiliary exercise equipment as claimed in claim 3, wherein the
plurality of members of the footrest are a front half and a back
half,wherein the footrest is configured so that the back half is bent
downward with respect to the front half.

6. The auxiliary exercise equipment as claimed in claim 2, wherein the
plurality of members of the footrest are separately arranged to right and
left.

7. The auxiliary exercise equipment as claimed in claim 6, wherein the
plurality of members of the footrest are an inside half and an outside
half,wherein the footrest is configured so that the inside half is bent
downward with respect to the outside half.

8. The auxiliary exercise equipment as claimed in claim 6, wherein the
plurality of members of the footrest are an inside half and an outside
half,wherein the footrest is configured so that the outside half is bent
downward with respect to the inside half.

9. The auxiliary exercise equipment as claimed claim 1, wherein the
footrest is configured so as to support the user's foot in the standing
position.

10. The auxiliary exercise equipment as claimed in claim 1, further
comprising:a foot support platform for supporting the footrest;a seat for
supporting buttocks of the user while a sole of the user is rested on a
rest surface of the footrest; anda seat driving unit being configured to
displace the seat by using a driving source so as to change a weight
acting, on a use's leg by the user's body weight;wherein the foot support
platform comprises a supporting base located in a fixed position, and a
supporting mechanical part configured to support the footrest with
respect to the supporting base while biasing the footrest upward so that
the footrest can reciprocate in the vertical direction,wherein the
rest-surface of the footrest is formed so as to slant downward along the
direction from a heel of the user toward a toe of the user,wherein the
supporting mechanical part is configured to relatively move a part of the
back of the footrest larger than a part of the front of the footrest when
the weight acting on the user's leg by the user's body weight increases.

11. The auxiliary exercise equipment as claimed in claim 10, further
comprising:a detector for detecting a muscle activity of the user's leg
anda controller being configured to control a movement distance of the
footrest moved by the supporting mechanical part according to a result of
the muscle activity detected by the detector.

12. The auxiliary exercise equipment as claimed in claim 11, wherein the
detector is configured to detect a muscle activity of either hamstrings
or triceps surae muscles of the user, the hamstrings including a biceps
femoris muscle, a semimembranosus muscle and a semitendinosus muscle, the
triceps surae muscles including a gastrocnemius muscle and a soleus
muscle.

13. The auxiliary exercise equipment as claimed in claim 2, wherein the
footrest is configured so as to support the user's foot in the standing
position.

14. The auxiliary exercise equipment as claimed in claim 3, wherein the
footrest is configured so as to support the user's foot in the standing,
position.

15. The auxiliary exercise equipment as claimed in claim 4, wherein the
footrest is configured so as to support the user's foot in the standing
position.

16. The auxiliary exercise equipment as claimed in claim 5, wherein the
footrest is configured so as to support the user's foot in the standing
position.

17. The auxiliary exercise equipment as claimed in claim 6, wherein the
footrest is configured so as to support the user's foot in the standing
position.

18. The auxiliary exercise equipment as claimed in claim 7, wherein the
footrest is configured so as to support the user's foot in the standing
position.

19. The auxiliary exercise equipment as claimed in claim 8, wherein the
footrest is configured so as to support the user's foot in the standing
position.

Description:

[0002]In the past, there have been proposed various types of auxiliary
exercise equipments which assist a user to stretch user's muscles without
effort but with an aid of external forces being applied to the user in
order to give an exercise effect. These equipments are known to be
configured to apply a force of bending a joint of the user for stretching
the muscles associated with the joint (for example, see Japanese Patent
Application Laid-Open No. 2007-37850). This auxiliary exercise equipment
assists a user to contract the muscles of the user's femoral area almost
without bending the user's knee. It is possible to strengthen the muscles
of the femoral area even if the user has knee pain. In addition, because
a volume of the femoral area's muscles is large, sugar metabolism
associated with muscles contraction is efficiently enhanced. Therefore,
it's expected to contribute to the improvement of lifestyle diseases such
as diabetes.

[0003]However, in this configuration, the user exercises to keep the
user's body weight on an entire sole of the user's foot with an aid of
external forces. Thus, this equipment has a problem that only particular
parts of the muscles can be strengthened and it is impossible to
stimulate broader parts of the muscles.

[0004]Another auxiliary exercise equipment comprises a foot support
platform for supporting the user's foot, and a seat. The equipment
assists the user to strain and relax the muscles of the user's femoral
area by moving the seat almost without bending the user's knee while
supporting the user's buttocks on a contact surface of the seat (for
example, see Japanese Patent Application Laid-Open No, 2007-181731). This
equipment moves a position of the seat and changes a rate of a weight
supported by the seat to the user's body weight. This allows a weight
acting on the user's leg to change. When the weight acting on the user's
leg increases, a mounting surface of the foot support platform descends.
Thus, a bending angle of the user's knee is kept at almost a constant
angle.

[0005]Compared with an equipment which is configured so that almost the
user's full body weight acts on the leg, the above equipment can reduce a
load by such operation. And even if the user is, for example, a diabetic
patient and has knee pain, it becomes possible for the user to strengthen
the muscles of the femoral area by contracting said muscles almost
without bending the user's knee. In addition, because a volume of said
muscles is large, it is also expected that sugar metabolism associated
with muscles contraction contributes to improvement of lifestyle
diseases. Furthermore, the user can exercise passively without effort by
using a driving source and moving the seat. Thus, coupled with a light
load, it becomes possible for the user to use the above equipment even if
the user has a poor exercise capacity or no interest in exercise.

[0006]By the way, in order to give an effect of exercise for quadriceps
femoris muscles while reducing a load of the user's knee joint, it is
important for the equipment having the described above configuration to
contract hamstrings (a biceps femoris muscle, a semimembranosus muscle
and a semitendinosus muscle) and a crural muscle at the same time and to
reduce a shear force acting on the knee joint. Therefore, in the old
equipment described in Japanese Patent Application Laid-Open No.
2007-181731, a mounting surface of the foot support platform (that is, a
top surface) slants downward so that a toe side of the user descends (in
a downward direction along a direction from a heel toward a toe), and
thereby a load is applied to the toe side larger while a foot joint of
the user is plantarflexed. By such configuration, triceps surae muscles
(a gastron-emius muscle and a soleus muscle) can be contracted, and at
the same time hamstrings being coordination muscles can also be
contracted. As a result, muscles around the knee can be contracted
simultaneously.

[0007]However, in the above mentioned prior art, the mounting surface of
the foot support platform only slants downward along the direction from
the heel toward the toe. As a result, the prior art has a problem that a
load is rarely applied to a heel side of the user according to how the
user rides on the seat or an individual difference of a physique, when
the seat is moved and the weight acting on the user's leg increases. When
the load is applied to the heel side larger than the toe side, there is a
possibility that too much load may be applied to the knee joint of the
user. Therefore, it's expected to prevent too much load from being
applied to the knee joint and to strengthen the muscles around the knee.

DISCLOSURE OF THE INVENTION

[0008]It is an object of the present invention to provide an auxiliary
exercise equipment which is capable of strengthen a particular muscle, by
concentrating a user's body weight in a part of a user's sole and
preventing the body weight from being applied to a remaining part of the
sole.

[0009]An auxiliary exercise equipment of the present invention comprises a
footrest 21 for supporting a foot of a user (M). The footrest 21 is
configured so that a part of the footrest 21 relatively retreats from a
remaining part of the footrest 21 and thereby is made apart from the foot
while the remaining part of the footrest 21 supports the foot.

[0010]In this configuration (hereinafter, called a first configuration),
when the foot of the user (M) is rested on the footrest 21, the part of
the footrest 21 on which the foot is rested is made apart from the foot
and the remaining part of the footrest 21 supports the foot. As a result,
the user (M) has to support almost the user (M)'s full body weight with
the remaining part of the footrest 21, and thus a particular muscle can
be strengthened.

[0011]In an embodiment, the footrest 21 comprises a plurality of members.
The footrest 21 is configured so that at least one of the plurality of
members is bent with respect to a remaining member(s) of the plurality of
members and thereby is made apart from the foot of the user (M). In this
configuration, the part of the footrest 21 can be relatively moved, with
respect to the remaining of the footrest by a simple configuration.

[0012]In an embodiment, the plurality of members of the footrest 21 are
separately arranged back and forth. In this configuration, if a front
member 21F of the footrest 21 is bent downward, the user (M) supports
user (M)'s body weight with a back side of the foot and thereby a
particular muscle can be strengthened. Or if a back member 21B of the
footrest 21 is bent downward, the user (M) supports user (M)'s body
weight with a front side of the foot and thereby a particular muscle can
be strengthened.

[0013]In an embodiment, the plurality of members of the footrest 21 are a
front half 21F and a back half 21B. The footrest 21 is configured so that
the front half 21F is bent downward with respect to the back half 21B. In
this configuration, mainly an anterior tibial muscle and muscles of a toe
can be strengthened.

[0014]In an embodiment, the plurality of members of the footrest 21 are a
front half 21F and a back half 21B. The footrest 21 is configured so that
the back half 21B is bent downward with respect to the front half 2F. In
this configuration, mainly muscles of a toe, a sole and a calf can be
strengthened.

[0015]In an embodiment, the plurality of members of the footrest 21 are
separately arranged to right and left. In this configuration, when an
outside member of the footrest 21 is bent downward, the user (M) supports
user (M)'s body weight with an inside of the foot of the user (M) and
thereby a particular muscle can be strengthened. Or when an inside member
of the footrest 21 is bent downward, the user (M) supports the body
weight with an outside of the foot and thereby a particular muscle can be
strengthened.

[0016]In an embodiment, the plurality of members of the footrest 21 are an
inside half and an outside half. The footrest 21 is configured so that
the inside half is bent downward with respect to the outside half in this
configuration, when an inside member of the footrest 21 is bent downward,
outside muscles of the foot of the user (M) can be strengthened and
thereby knock-knee can be corrected.

[0017]In an embodiment, the plurality of members of the footrest 21 are an
inside half and an outside half. The footrest 21 is configured so that
the outside half is bent downward with respect to the inside half in this
configuration, when an outside member of the footrest 21 is bent
downward, inside muscles of the foot of user (M) can be strengthened and
thereby bow-legs can be corrected.

[0018]In an embodiment, the footrest 21 is configured so as to support the
foot of the user (M) in the standing; position. In this configuration, a
full body weight of the user (M) can be applied to the foot of the user
(M) and thereby highly-loaded and high-efficient training can be
achieved.

[0019]In the first configuration, the auxiliary exercise equipment further
comprises a foot support platform 2 for supporting the footrest 21, a
seat 51 for supporting buttocks of the user (M) while a sole of the user
(M) is rested on a rest-surface 21A of the footrest 21, and a seat
driving unit 52 being configured to displace the seat by using a driving
source so as to change a weight acting on a leg of the user (M) by the
user (M)'s body weight. It's preferred that, the foot support platform 2
comprises a supporting base 1a located in a fixed position, and a
supporting mechanical part 210 configured to support the footrest 21 with
respect to the supporting base 1a while biasing the footrest upward so
that the footrest 21 can reciprocate in the vertical direction. It's
preferred that the rest-surface 21A of the footrest 21 is formed so as to
slant downward along the direction from a heel of the user (M) toward a
toe of the user (M), and the supporting mechanical part 210 is configured
to relatively move a part back 21B of the footrest 21 larger than a front
part 21F of the footrest 21 when the weight acting on the leg increases.

[0020]In this configuration (hereinafter, called a second configuration),
the supporting mechanical part 210 is configured to relatively move the
back part 21B larger than the front part 21F when the weight acting on
the leg increases. Thus, a load can be applied to the toe side larger
than the heel side, regardless of how the user (M) rides on the seat 51
or an individual difference of a physique. As a result, it becomes
possible to prevent too much load from being applied to the knee joint
and to strengthen the muscles around the knee.

[0021]In the second configuration, the auxiliary exercise equipment may
comprises a detector 61 for detecting a muscle activity of the user (M)'s
leg, and a controller 62 being configured to control a movement distance
of the footrest 21 moved by the supporting mechanical part 210 according
to a result of the muscle activity detected by the detector 61. In this
configuration, the movement distance of the footrest 21 is controlled
according to the degree of the muscle activity of the user (M)'s leg, and
thereby an appropriate, load can be applied to the muscles around the
knee.

[0022]In the second configuration, the detector 61 may be configured to
detect a muscle activity of either hamstrings or triceps surae muscles of
a user (M). The hamstrings include a biceps femoris muscle, a
semimembranosus muscle and a semitendinosus muscle. The triceps surae
muscles include a gastrocnemius muscle and a soleus muscle.

BRIEF DESCRIPTION OF THE DRAWINGS

[0023]Preferred embodiments of the invention will now be described in
further details. Other features and advantages of the present invention
will become better understood with regard to the following detailed
description and accompanying drawings where:

[0024]FIG. 1A is a longitudinal sectional side view showing a footrest,
which is set up in a central position, according to an embodiment of the
present invention, and FIG. 1B is a front sectional view showing said
footrest;

[0025]FIG. 2 is a longitudinal sectional side view showing said footrest
which is moved forward from said central position;

[0026]FIG. 3 is an overall schematic side view according to said
embodiment;

[0027]FIG. 4 is a plane perspective view showing a housing according to
said embodiment;

[0028]FIG. 5 is an overall exploded perspective view according to said
embodiment;

[0029]FIG. 6 is a cross-section view of an essential part seen from the
hack of said housing;

[0030]FIG. 7 is a cross-section view of an essential part of a guide
section according to said embodiment;

[0031]FIGS. 8A and 8B are block diagrams of a drive unit according to said
embodiment, respectively;

[0032]FIG. 9 is a cross-section view of an essential part of a foot
support platform according to said embodiment;

[0033]FIG. 10A is a longitudinal sectional side view showing a footrest,
which is set up in a central position, according to an embodiment of the
present invention, and FIG. 10B is a front sectional view showing said
footrest;

[0034]FIG. 11 is a longitudinal sectional side view showing said footrest
which is moved forward from said central position according to said
embodiment;

[0035]FIG. 12 is a front view of a footrest according to an embodiment of
the present invention;

[0036]FIG. 13 is a front view of a footrest according to an embodiment of
the present invention;

[0037]FIGS. 14A and 14B are schematic side views showing a foot support
platform according to an embodiment of the present invention,
respectively;

[0040]FIG. 17 is a block diagram of a control system according to an
embodiment of the present invention; and

[0041]FIG. 18 is a schematic side view showing a foot support platform
according to said embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION

[0042]An embodiment of an auxiliary exercise equipment of the present
invention is explained based on FIGS. 1 to 9. As shown in FIG. 3, the
equipment comprises a base 10 located on a fixed position, such as a
floor. A handle post (HP) is arranged on the base 10, and comprises a
handle (HD), which a user (M) in standing position grips with a hand if
needed, at the top. In addition, the base 10 is provided with a foot
support platform 2 (a left foot support platform 2a and a right foot
support platform 2b), a guide section 4 for restricting a travel path of
each of the left and right support platforms 2a and 2b, and a drive unit
3 for driving the foot support platform 2. A top surface of the foot
support platform 2 is called a rest-surface, and left and right feet of
the user (M) are rested on the rest-surface, respectively. The handle
(HD) and the handle post (HP) are not indispensable.

[0043]As shown in FIGS. 4 and 5, the base 10 comprises a housing 1 which
is composed of a supporting base 1a and an upper plate 1b. The supporting
base 1a shown in the figure is configured to have a rectangular
parallelepiped shape, although not limited to such a shape. For a
simplified explanation made hereinafter, the supporting base 1a is
illustrated to have a top surface parallel to the floor when it is placed
on the floor.

[0044]The upper plate 1b is disposed on the supporting base 1a, and is
coupled thereto to constitute the housing 1. The supporting base 1a is
provided with a left foot support platform 2a and a right foot support
platform 2b on which left and right feet of the user (M) are rested,
respectively. Also, the drive unit 3 is disposed on the supporting base
1a, for moving the left and right foot support platforms 2a and 2b. It is
noted that an arrow X shown in FIGS. 2 and 3 denotes a forward direction
of the equipment.

[0045]The upper plate 1b is formed with two openings 11a and 11b extending
in a thickness direction of the plate so as to expose the left and right
support platforms 2a and 2b, respectively. Each of the openings 11a and
11b is formed into a rectangular shape. Each of center lines along
longitudinal directions of the openings 11a and 11b slants with respect
to forward/rearward direction of the housing 1 so that the distance
between the center lines is larger at the front ends of the openings than
at the rear ends thereof.

[0046]As shown in FIG. 6, slide grooves 12 are provided on opposite width
ends of each of the openings 11a and 11b in communication therewith for
receiving flange 22b formed on each of footrest frames 22. Each of the
footrest frames 22 is cooperative with a footrest 21, on which a foot of
the user (M) is rested, to define each of the left and right foot support
platforms 2a and 2b, and comprises a main section 22a in the shape of a
rectangular barrel. Also, each of the footrest frames 22 is formed with
the flange 22b extending around an open face (upper face) over the entire
periphery of the main section 22a. In addition, each of the footrest
frames 22 has an integrally formed attachment plate 22c at a lower end
within the main section 22a.

[0047]The main section 22a has a longitudinal dimension as well as a width
dimension respectively less than those of the openings 11a and 11b, while
the flange 22b has such dimensions larger than those of the openings 11a
and 11b. Further, a distance between opposed bottoms of the slide grooves
12 is larger than a distance between opposite edges of the flange 22b.
Thus, each of the footrest frames 22 is allowed to move within the
confines of the slide groove 12 with respect to a width direction as well
as a longitudinal direction.

[0048]Each of footrests 21 is formed into a rectangular plate slightly
smaller than an inner periphery of the main section 22a to have such
dimensions as to rest a entire foot of the user (M). As will hereinafter
be described, a front half 21F and a back half 21B are connected by a
hinge 21C to constitute a footrest 21. An upper surface of the footrest
21 is made of a material or shaped to have a large coefficient of
friction. The footrest 21 is integrally formed around its lower periphery
with almost square bracket shaped frame members 21a and 21b.

[0049]A bearing plate 23 of square bracket shaped cross-section is fixed
to the top of a attachment plate 22e of a footrest frame 22 to have its
open end oriented upwardly. Axles 24 are provided at both ends of a hinge
21C in an extended condition to penetrate through leg members 23a of the
bearing plate 23, respectively Consequently the axles 24 are located so
as to extend in a width direction of the footrest 21, and the footrest 21
is allowed to swing about the axles 24 so as to move up and down at
forward and rearward ends of its longitudinal direction with respect to
the footrest frame 22. The above frame members 21a and 21b are provided
to conceal a gap formed between the footrest 21 and the footrest frame 22
when the footrest 21 swings relative to the footrest frame 29.

[0050]A truck 41 of square bracket shaped cross-section is fixed to the
bottom of the attachment plate 22c through the footrest frame 22 to have
its open end oriented downwardly. Each of leg members 41a located at the
truck 41 is provided on its exterior face with two wheels 42. The
supporting base 1a is formed on its upper surface with two fixed rails 43
for each of the left and right fool support platforms 2a and 2b. The
truck 41 is placed on the rails 43 so that the wheels 42 rolls in the
rail grooves 43a provided in the upper end of the rails 43. Derailment
prevention plates 44 are provided on top of 43a, respectively (see FIG.
7).

[0051]By the way, each of the rails 43 extends in a direction different
from a longitudinal direction of each of the openings 11a and 11b in the
housing 1. As described in the above, each of center lines along
longitudinal directions of the openings 11a and 11b slants so that the
distance between the center lines is larger at the front ends of the
housing 1 than at the rear ends thereof. Also, each of longitudinal
directions of the rails 43 slants in the like manner.

[0052]However, each of longitudinal directions of the rails 43 slants at a
larger angle than each of longitudinal directions of the openings 11a,
and 11b, in relation to the forward/rearward direction of the housing 1.
For example, if each of longitudinal directions of the openings 11a and
11b slants at an angle of 30° in relation to said forward/rearward
direction, each of longitudinal directions of the rails 43 slants at an
angle of 45°. In other words, when the feet are rested on the left
and right foot support platforms 2a and 2b so that center lines of the
feet are aligned with longitudinal directions of the openings ha and lib,
respectively, each of longitudinal directions of the rails 43 is
oriented, to such a direction as to prevent, a shear force from acting on
the knee joint even if the left and right foot support platforms 2a and
2b are moved along the rails 43 and thereby a position of each of the
feet is moved. Although the present embodiment illustrates a preferred
mode that the left and right foot support platforms 2a and 2b are moved
along the individual travel paths of shifting their positions both in the
forward/rearward direction and the lateral direction, it is possible to
determine the orientation of the rails 43 such that the left and right
foot support platforms 2a and 2b are moved either in the forward/rearward
direction or the lateral direction.

[0053]With the above arrangement, the left and right foot support
platforms 2a and 2b are allowed to reciprocate along the longitudinal
directions of the rails 43, respectively. Because the longitudinal
directions of the rails 43 slant relative to the longitudinal center
lines of the openings 11a and 11b, respectively, the footrests 21 and the
footrest frames 22 are allowed to move within the openings 11a and 11b
along the directions slanting with the longitudinal directions of the
openings 11a and 11b, respectively in other words, the above trucks 41,
the wheels 42, the rails 43 and the derailment prevention plates 44
function as guide sections 4 for restricting travel paths of the left and
right foot support platforms 2a and 2b, respectively.

[0054]As shown in FIG. 8A, a drive unit 3 shifts the position of the left
and right foot support platforms 2a and 2b. The drive unit 3 comprises a
driving source 31 for generating a driving force, a router 32 for
transmitting the driving force to the left and right foot support
platforms 2a and 2b, and reciprocator(s) 33 for using the driving force
to reciprocate the trucks 41 respectively along the rails 43. Although
the equipment of the present embodiment is configured to divide the
driving force at the router 32 and transmit the divided driving force to
two reciprocators 33, as shown in FIG. 5A, it is equally possible to
generate the reciprocating driving force at one reciprocator 33 and
divide the same at the router 32, as shown in FIG. 8B.

[0055]Details of the drive unit 3 are now explained. A rotary motor is
used as the driving source 31 (hereinafter, called a motor 31), and the
router 32 is coupled to an output shaft 31a of the motor 31.

[0056]The router 32 comprises a worm (a first gear) 32a coupled to the
output shaft 31a of the motor 31, and a pair of worm wheels (second gear
wheels) 32b engaging with the worm 32a. The worm 32a and the two worm
wheels 32b are held within a gearbox 34 fixed to the supporting base 1a.
The gearbox 34 is composed of a gear case 34a with a top opening and a
lid 34b fitted in the opening of the gear case 34a. A pair of bearings
32c is mounted between the gear case 34a and the lid 34b to bear the
opposite longitudinal ends of the worm 32a.

[0057]A rotary shaft 35 is held by the gear case 34a and the lid 34b and
extends through the worm wheel 32b. And the rotary shaft 35 is coupled to
the worm wheel 32b to be driven thereby to rotate. Furthermore, the
rotary shaft 35 is formed at its upper end with a coupling section 35a
with non-circular cross-section (rectangular one in the illustrated
instance).

[0058]The motor 31 is mounted on a holder member 34c of the gear case 34a
and on a holder plate 13a secured to the supporting base 1a, and is fixed
to the supporting base 1a by means of the lid 34b fitted over the gear
case 34a and a retainer plate 13b coupled to the holder plate 13a.

[0059]As shown in FIG. 9, the reciprocator 33 comprises a crank plate 36
coupled at its one end to the coupling section 35a of the rotary shaft
35, and a crank rod 38 coupled to the crank plate 36 by means of a crank
shaft 37. The crank shaft 37 has its one end fixed to the crank plate 36
and has the other end received in the bearing 38a carried on one end of
the crank rod 38. That is, the crank rod 38 has its one end rotatively
coupled to the crank plate 36, while the other end of the crank rod 38 is
coupled to the truck 41 by means of an axle 38b so as to be rotatively
coupled thereto.

[0060]As is apparent from the above, the crank rod 38 functions as a
motion converter to translate the rotary motion of the worm wheel 32b
into a reciprocatory motion of the truck 41. The crank rod 38 is provided
for each of the worm wheels 32b, and the trucks 41 are provided to the
left and right foot support platforms 2a and 2b, respectively. Thus, the
crank rods 38 function as the individual motion converters for
translating the rotary motion of the worm wheels 32b into the
reciprocating motions of the left and right foot support platforms 2a and
2b, respectively.

[0061]As described in the above, the truck 41 has its travel path
restricted by the wheels 42 and the rails 43. Therefore, the trucks 41
reciprocate along longitudinal directions of the rails 43, respectively
as the worm wheels 32b rotate. That is, the rotation of the motor 31 is
transmitted to the crank plate 36 by way of the worm 32a and the worm
wheels 32b, so that the crank rod 38 coupled to the crank plate 36 makes
the trucks 41 reciprocate linearly along the rails 43. As a result, the
footrest frames 22 coupled to the trucks 41 are driven to reciprocate
along the rails 43. In other wards, the left and right foot, support
platforms 2a and 2b are driven to reciprocate along the longitudinal
directions of the rails 43, respectively.

[0062]In the present embodiment, the worm 32a and the two worm wheels 32b
are responsible for routing the driving force into two channels
respectively for driving the left and right foot support platforms 2a and
2b. Thus, the drive unit 3 drives the left and right foot support
platforms 2a and 2b in a manner linked to each other. Here, the worm
wheels 32b are engaged with the worm 32a at different portions spaced
apart by 180°. Therefore, the right foot support platform 2b comes
to a forward end of its movable range when the left foot support platform
2a comes to a rear end of its movable range. As the left foot support
platform 2a comes to the right end of its movable range when it comes to
the rear end of the movable range, and the right foot support platform 2b
comes to the right, end of its movable range when it comes to the forward
end of the movable range, the left and right foot support platforms 2a
and 2b shift in the same direction along the lateral direction.

[0063]As apparent from the above, it is possible to give a desired phase
difference of the movement, between the left and right foot support
platforms 2a and 2b by varying positions of engaging the worm 32a with
the worm wheels 32b. The phase difference of 180° is effective, to
minimize, the shifting of a weighted center of the user (M) along the
forward/rearward direction, enabling the exercise even by the user (M)
suffering from lowered balancing capability. Alternatively, when no phase
difference is given, the equipment necessitates the shifting movement of
the weighted center along the forward/rearward direction, thereby
developing an exercise not only for the leg muscles but also for lower
back muscles of the user (M) maintaining the balancing capability.

[0064]As apparent from the above, the drive unit 3 can drive the left and
right foot support platforms 2a and 2b to move in the forward/rearward
direction and at the same time to move in the lateral direction in the
linked manner to each other. Here, the left and right foot support
platforms 2a and 2b are driven to reciprocate linearly along the rails 43
so as to move in directions different from forward/rearward directions of
the feet, respectively. For example, the left and right foot support
platforms 2a and 2b move in directions inclined at an angle of 45°
relative, to the forward/rearward direction of the housing 1. This travel
distance is over 20 mm, for example.

[0065]Now, the footrest 21 provided on each of the left and right foot
support platforms 2a and 2b is allowed to swing about the axle 24
relative to the footrest frame 22, enabling to vary height positions of
the forward end as well as the rearward end of the footrest 21. That is,
it's possible to vary height positions of the toe and the heel of the
foot rested on the footrest 21, and this enables the plantar flexion and
dorsal flexion of an ankle joint.

[0066]Here, in order to link the swinging movement, of the footrest 21
about the axle 24 with the reciprocating movement thereof along the rail
43, the supporting base 1a is provided at a portion along the travel path
of the footrest 21 with a guide rail 17 as a guide section 4, as shown in
FIG. 1.

[0067]As shown in FIG. 1, the guide rail 17 formed in the base 10
restricts the travel path of each of the left and right foot support
platforms 2a and 2b. The guide rail 17 allows each of the left and right
foot support platforms 2a and 2b to move with respect to nearly the
forward/rearward direction, and makes a portion of the foot support
platform 2 go backward when the foot support platform 2 moves along the
travel path.

[0068]Caves 15 are formed within the base 10 so as to extend along the
travel path of each of the left and right foot support platforms 2a and
2b. Grooves 16 are formed so as to pass through an upper wall of the
caves 15, respectively, and their longitudinal directions extend along
nearly the forward/rearward direction. In the present embodiment, the
more the left foot support platform 2a goes forward, the more its travel
path slants leftward. Therewith, the more the right foot support platform
2b goes forward, the more its travel path slants rightward. The grooves
16 are formed along such travel paths.

[0069]A footrest 21 of each of the left and right foot support platforms
2a and 2b is composed of a front half 21F and a back half 21B. A length
of the front half 21F is almost twice as long as that of the back half
21B, with respect to a longitudinal direction of the footrest 21. A hinge
21C, connects a back end of the front half 21F with a front end of the
back half 21B. Thus, the footrest 21 is configured to be bent at the
hinge 21C which is arranged at about one third of a length of footrest 21
away from a back end of the foot support platform 2. The front half 21F
is a rest section on which a toe and a central part of the foot are
rested, and the back half 21B is a rest section on which a heel is
rested. At a lower surface of the front half 21F, a front drooping
section 25a is formed so as to project downward from a center of a
forward section of the lower surface, and a central drooping section 25b
is formed so as to project downward from a center of a backward section
of the lower surface. A back drooping section 25c is formed so as to
project downward from a center of a lower surface of the back half 21B.
The drooping sections 25 (25a˜c) are inserted into the grooves 16,
respectively, and each of bottom ends of the sections 25 is arranged into
the cave 15 of the base 10. Each of said bottom ends is provided with a
crossbar 26. In the cave 15, the crossbar 26 has a length longer than a
width of the groove 16 and its longitudinal direction is directed
parallel to a width direction of the groove 16. The guide rail 17 is
formed on the bottom surface of the cave 15 arranged along the travel
path of the base 10. That is, the guide rail 17 is composed of a front
guide rail 17a for guiding the crossbar 26 of the front drooping section
25a, a central guide rail 17b for guiding the crossbar 26 of the central
drooping section 25b, and a back guide rail 17c for guiding the crossbar
26 of the back drooping section 25c.

[0070]The guide rail 17 houses the crossbars 26 within, and determines
vertical positions of the crossbars 26 according to front-back positions
of the crossbars 26, in the present embodiment, the guide rail 17 is
roughly shaped like a box, and its inside is provided with travel spaces
18 which allow the crossbars 26 to move in a forward/backward direction,
respectively. Grooves 19 are formed so as to pass through upper walls of
the travel spaces 18 and to extend along longitudinal directions (that
is, travel directions) of the travel spaces 18, respectively. A width of
each of the grooves 19 is shorter than a length of each of the crossbars
26 and is a little longer than a width of each of the drooping sections
25. The drooping sections 25 are inserted into the travel spaces 18
through the grooves 19 and the crossbars 26 are arranged within the
travel spaces 18, respectively, and thereby the crossbars 26 can be
prevented from falling out of the grooves 19. The front guide rail 17a
extends diagonally downward front so that the more a travel space 18 goes
forward, the more a position of a crossbar 26 is located downward. The
central guide rail 17b extends diagonally upward front so that the more a
travel space 18 goes forward, the more a position of a crossbar 26 is
located upward. A front half of the back guide rail 17c extends flatly,
and a back half thereof extends diagonally downward hack so that the more
a travel space 18 goes backward, the more a position of a crossbar 26 is
located downward.

[0071]Herewith, an upper surface of the front half 21F is almost flush
with that of the back half 21B and their upper surfaces are almost
horizontal, as shown in FIG. 1, when each of the left and right foot
support platforms 2a and 2b is located at almost a center relative to a
forward/backward direction of the travel path (called a central
position).

[0072]As shown in FIG. 2, when a footrest 21 moves forward (in the figure,
rightward) relative, to said central position, a front half 21F slants
diagonally downward front and a back half 21B slants diagonally downward
back and a foot is plantarflexed. The length of the front half 21F is
longer than that of the back half 21B, and a toe maintains to be rested
on the front half 21F, and a heel is away from the back half 21B, and
thereby muscles including a sole and a calf can be strengthened.

[0073]When the footrest 21 moves backward relative to said central
position, both of the front half 21F and the back half 21B, not shown,
slant diagonally downward back. The footrest 21 keeps a condition that an
upper surface of the front half 21F is almost flush with that of the back
half 21B, and the foot is dorsiflexed, but an entire foot maintains to be
rested on the footrest 21.

[0074]As described above, the footrest 21 is configured so that a part
thereof can go backward. That is, the footrest 21 is configured so that a
part thereof relatively retreats from a remaining part thereof and
thereby is made apart from a foot, while said remaining part supports the
foot. Herewith, a body weight of the user (M) is focused in a part of the
sole, and thus a particular muscle can be strengthened. In addition, the
footrest 21 comprises a plurality of members, and at least one of the
plurality of members is bent with respect to a remaining member(s) of the
plurality of members. Therefore a part of the footrest 21 can be
relatively moved with respect to a remaining part of the footrest 21 by a
simple configuration.

[0075]Furthermore, the plurality of members of the footrest 21 are
separately arranged back and forth, and at least one of the members is
bent with respect to a remaining member(s). Therefore if a front member
of the footrest 21 is bent downward, the user (M) supports the user (M)'s
body weight with a back side of the user (M)'s foot and thereby a
particular muscle can be strengthened. Or if a hack member of the
footrest 21 is bent downward, the user (M) supports the user MA body
weight with a front side of the user (M)'s foot and thereby a particular
muscle, can be strengthened. For example, when the front member of the
footrest 21 is bent downward with respect to the back member, muscles
including a sole and a calf can be strengthened.

[0076]Then, another embodiment is explained based on FIG. 10. If some
members shown in FIG. 10 are the same as members explained in the above
embodiment shown in FIGS. 1 to 9, said some members are putted the same
numerals on, respectively, and the explanation thereof is omitted.
Members other than members explained in the above embodiment are
explained.

[0077]A footrest 21 of each of a left and right foot support platforms 2a
and 2b is composed of a front half 21F and a back half 21B. In the
present embodiment, a length of the front half 21F is almost half as long
as that of the back half 21B, with respect to a longitudinal direction of
the footrest 21. A hinge 21C connects a back end of the front half 21F
with a front end of the back half 21B. Thus, the footrest 21 is
configured to be bent at the hinge 21C which is arranged at about one
third of a length of the footrest 21 away from a front end of the foot
support platform 2. The front half 21F is a rest section on which a toe
is rested, and the back half 21B is a rest section on which a heel and a
central part of the foot are rested. A front drooping section 25a is
formed so as to project downward from a center of the lower surface of
the front half 21F. At a lower surface of the back half 21B, a central
drooping section 25b is formed so as to project downward from a forward
section of the lower surface, and a back drooping section 25c is formed
so as to project downward from a backward section of the lower surface. A
bottom surface of the base 10 is provided with a front guide rail 17a for
guiding a crossbar 26 of the front drooping section 25a, a central guide
rail 17b for guiding a crossbar 26 of the central drooping section 25b,
and a back guide rail 17c for guiding a crossbar 26 of the back drooping
section 25c.

[0078]The front guide rail 17a comprises a front half part and a back half
part. The front and back half parts extend diagonally downward front,
respectively, so that the more a travel space 18 goes forward, the more a
position of a crossbar 26 is located downward. However, a slant of the
front half part is larger than that of the back half part. The central
guide rail 17b extends diagonally downward front so that the more a
travel space 18 goes forward, the more a position of a crossbar 26 is
located downward. The back guide rail 17c extends diagonally upward front
so that the more a travel space 18 goes forward, the more a position of a
crossbar 26 is located, upward.

[0079]Herewith, when the left and right foot support platforms 2a and 2b
are located at a central position of the travel path, respectively, an
upper surface of the front half 21F is almost flush with that of the back
half 21B and their upper surfaces are almost horizontal, as shown in FIG.
10.

[0080]As shown in FIG. 11, when the footrest 21 moves forward (in the
figure, rightward) relative to said central position, the front half 21F
and the back half 21B slant diagonally downward front, respectively.
However, a slant of the front half 21F is larger than that of the back
half 21B. A length of the front half 21F is shorter than that of the back
half 21B, with respect to a longitudinal direction of the foot support
platform 2. A heel maintains to be rested on the back half 21B and a toe
is away from the front half 21F. As a result, muscles of an anterior
tibial and a toe can be strengthened.

[0081]When the footrest 21 moves backward relative to said central
position, if) the front half 21F and the back half 21B, not shown, slant
diagonally downward back. The footrest 21 keeps a condition that an upper
surface of the front half 21F is almost flush with that of the back half
21B, and the foot is dorsiflexed, but an entire foot maintains to be
rested on the footrest 21.

[0082]Herewith, a front member of the footrest 21 is bent downward with
respect to a back member thereof, and thereby the muscles of an anterior
tibial and a toe can be strengthened.

[0083]Now, yet another embodiment is explained. If some members are the
same as members explained in the above embodiment shown in FIGS. 1 to 9,
said some members are putted the same numerals on, respectively, and the
explanation thereof is omitted. Members other than members explained in
the above embodiment, are explained mainly.

[0084]In the present embodiment, a footrest 21 is configured so that a
part thereof relatively retreats from a remaining part thereof and
thereby is made apart from a foot while said remaining part supports the
foot. For example, the footrest 21 is composed of separate members
relative to right and left, and these members are arranged adjacently
each other. The footrest 21 is configured that at least one of a
plurality of members is bent with respect to a remaining member(s) of the
members and thereby is made apart from a user (M)'s foot. Herewith, when
an outside half of the footrest 21 is bent downward, the user (M)
supports the user (M)'s body weight with an inside of the user (M)'s foot
and thereby a particular muscle can be strengthened. Or when an inside
half of the footrest 21 is bent downward, the user (NI) supports the user
(M)'s body weight with the outside of the user (M)'s foot and thereby a
particular muscle can be strengthened.

[0085]In the present embodiment shown in FIG. 12, the outside half is bent
downward with respect to the inside half. A footrest 21 of each of the
left and right foot support platforms 2a and 2b is composed of a right
and left side members 21R and 21L. A hinge 21C connects a left, end of
the right side member 21R and a right end of the left side member 21L.
Thus, the footrest 21 is configured to be bent at the hinge 21C which is
arranged at a central part with respect to a horizontal direction of the
foot support platform 2. As shown in FIG. 12, the right foot support
platform 2b is configured that the right side member 21R of a fifth
finger side is bent downward. Not shown, the left foot support platform
2a is configured that the left side member 21L of a fifth finger side is
bent downward.

[0086]Herewith, the outside half of the footrest 21 is bent downward with
respect to the inside half and thereby inside muscles of the foot can be
strengthened and bow-legs can be corrected.

[0087]Also, in the present embodiment shown in FIG. 13, the inside half is
bent downward with respect to the outside half. As shown in FIG. 13, the
right foot support platform 2b is configured that the left side member
21L of a first toe side is bent downward. Not shown, the left foot
support platform 2a is configured that the right side member 21R of a
first toe side is bent downward.

[0088]Herewith, an inside half of the footrest 21 is bent downward with
respect to an outside half and thereby outside muscles of the foot, can
be strengthened and knock-knee can be corrected.

[0089]FIGS. 14 to 16 show an auxiliary exercise equipment according to an
embodiment of the present invention. As shown in FIGS. 15 and 16, the
equipment of the present embodiment comprises a base 10 located on a
fixed position, such as a floor. A seat support 50 and a handle post (HP)
are arranged on the base 10. An upper end of the seat support 50 is
provided with a seat 51 for supporting buttocks of a user (M). An upper
of the handle post (HP) is provided with a handle (HD) which the user (M)
in standing position grips with a had if needed. On the base 10, a foot
support platform 2, of which a top surface is a rest-surface 21A, is
formed at a position between the seat support 50 and the handle post
(HP). A sole of the user (M) is rested on the rest-surface 21A and
thereby a foot position is regulated.

[0090]The seat support 50 is provided with a seat driving unit 52 for
swinging the seat 51, and a elevator mechanical part 53 for moving up and
down the seat 51 and the seat driving unit 52 with respect to the base
10. That is, the elevator mechanical part 53 moves up and down the seat
51 and the seat driving unit 52 with respect to the base 10, and thereby
a flexion angle "θ" of a knee of the user (M) can be adjusted when
the buttocks is put on a contact surface 51a of the seat 51 and the sole
is rested on the rest-surface 21A.

[0091]The seat driving unit 52 swings the seat 51 to move a position of
the buttocks, for the user (M) of which the buttocks is put on the
contact surface 51a and of which the sole is rested on the rest-surface
21A. Therefore, a weight acting on the leg of the user (M) by the user
(M)'s body weight is changed. That is, when the equipment supports the
user (M) while dispersing a weight acting on by the user (M)'s body
weight into the buttocks and the legs, a weight supported by the buttocks
is increased or decreased by moving the position of the buttocks. As a
result, a weight acting on the legs by the user (M)'s body weight can be
changed.

[0092]Here, when the knee is bent to a predetermined angle and a rate of
the user (M)'s body weight supported by the seat 51 decreases, a load
acting on the user (M)'s femoral area increases as bending the knee like
a squat exercise. Thus, it becomes possible to contract muscles of the
femoral area. That is, when the seat driving unit 52 swings the seat 51,
muscles of the femoral area alternates between excitation and relaxation
through not so much a spontaneous exercise but a passive exercise. In
other words, the seat driving unit 52 swings the seat 51 and thereby it
becomes possible to exercise muscles of the femoral area mainly.

[0093]It is preferred to set a swing direction of the seat 51 so as to
prevent a shear force from acting on a knee joint. As shown in FIG. 16,
when the buttocks of the user (M) are supported by the contact surface
51a of the seat 51, the feet of the user (M) becomes a condition that a
distance between toes is larger than a distance between heels and such
condition is natural attitude. An opening angle "θ2" between the
feet can be determined by positions of the foot support platform 2 on
which the feet are rested. Consequently the seat 51 is swung along a
direction of a center line connecting a toe and a heel of each of the
feet when the feet are rested on the foot support platform 2, and thereby
the user (M) can exercise passively without the shear force acting on the
knee joint. That is, periods of moving diagonally frontward right and
diagonally frontward left is set up when the seat 51 moves forward from
it back end of a swing range, and thereby almost the user (M)'s body
weight can act on the femoral area of each of the legs without the shear
force acting on the knee joint.

[0094]In addition, the contact surface 51.a of the seat 51 is almost a
horizontal surface in an example shown in FIG. 15. However, the user (M)
performs passively an exercise, which induces contracting muscles of the
femoral area by means of changing a weight acting on the legs by the user
(M)'s body weight, and thus it's preferred that the contact surface in
slants diagonally downward front along a swing direction of the seat 51.
That is, it's preferred that in regard to a front end of the seat 51 a
part supporting right buttocks of the user (M) slants downward and
diagonally frontward right, and a part supporting left buttocks of the
user (M) slants downward and diagonally frontward left. The seat 51
having such a shape allows the weight acting on the leg to increase
easily, and thereby high-efficient training can be achieved.

[0095]Then, a foot support platform 2 of this embodiment is explained. As
shown in FIGS. 14A and 14B, the foot support platform 2 comprises a
supporting base 1a which is fastened to a base 10 and thereby is arranged
in place a footrest 21 which is provided with a rest-surface 21A slanting
downward along a direction from a heel of the user (M) toward a toe of
the user (M) (in FIG. 14, leftward), and a supporting mechanical part 210
which is configured to support the footrest 21 with respect to the
supporting base 1a while biasing the footrest 21 upward so that the
footrest 21 can reciprocate in the vertical direction. The footrest 21 is
composed of two members, and the division between the members is near a
center in a longitudinal direction of the footrest 21. That is, the
footrest 21 is divided in a front half 21F located in a toe side and a
back half 21B located in a heel side. A connection mechanism (not shown)
connects the front half 21F and the back half 21B so that they can move
with respect to a vertical direction.

[0096]The supporting mechanical part 210 comprises a first movable plate
211, a second movable plate 212, a first spring 213 and a second spring
214. The first and second movable plates 211 and 212 are formed by narrow
and long plate members, respectively, and have the same shape and the
same size each other. A front end of the first movable plate 211 is
supported pivotally by a projection part which projects downward from an
end part of the front half 21F, and a back end thereof is supported
pivotally by a back end of the supporting base 1a. On the other hand, a
front end of the second movable plate 212 is supported pivotally by a
projection part which projects upward from an end part, of the supporting
base 1a, and a back end thereof is supported pivotally by a back end of
the back half 21B. The first and second movable plates 211 and 212 are
connected rotatably with a pin 215 which is located at some distance
forward from a center in a longitudinal direction. The first spring 213
biases the front half 21F upward with respect to the supporting base 1a,
and the second spring 214 biases the back half 21B upward. However, a
spring constant of the second spring 214 is smaller than that of the
first spring 213.

[0097]Therefore, when the sole is rested on the rest-surface 21A of the
footrest 21 and the weight acting on the leg increases and the front half
21F, which contacts with the sole in a toe side, resists the stress of
the first spring 213 to move downward (descent), the first movable plate
211 rotates in the counterclockwise direction around the back end
supported pivotally by the supporting base 1a and thereby the second
movable plate 212, which is connected the first movable plate 211 with
the pin 215, rotates in the clockwise direction around the front end
supported pivotally by the supporting; base 1a. Here, a position, where
the first and second movable plates 211 and 212 are connected, (that is,
a position of the pin 215) is located at some distance forward from a
center in a longitudinal direction of each of the first and second
movable plates 211 and 212. Thus, a downward travel distance (descent
distance) of the back half 21B is larger than that of the front half 21F.

[0098]In order to this configuration, the sole in a heel side is away from
the back half 21B of the footrest 21 and the weight acts on only the sole
in the toe side which contacts with the front half 21F of the footrest 21
when the sole is rested on the rest-surface 21A of the footrest 21 and
the weight acting on the leg increases.

[0099]And then, in the present embodiment, the supporting mechanical part
210 allows the back half 21B to move downward relatively larger than the
front half 21F when the weight acting on the leg increases. Thus, a load
can be applied to the toe side larger than the heel side, regardless of
how the user (M) rides on the seat 51 or an individual difference of a
physique. As a result, it becomes possible to prevent too much load from
being applied to the knee joint, and to strengthen the muscles around the
knee.

[0100]FIGS. 17 and 18 show a control system and a foot support platform of
an auxiliary exercise equipment according to an embodiment of the present
invention, respectively. The present embodiment is characterized that the
equipment comprises a detector 61 for detecting a muscle activity of the
user (M)'s legs, and a controller 62. The controller 62 is configured to
control a movement distance of the footrest 21 (the back half 21B) moved
by the supporting mechanical part 210 according to a result of the muscle
activity detected by the detector 61. However, members other than these
members are the same as the members of the above embodiment shown in
FIGS. 14 to 16. Thus, such members are putted the same numerals on,
respectively, and the illustration and explanation thereof are omitted.

[0101]As shown in FIG. 18, the supporting mechanical part 210 of the
present embodiment comprises a first spring 213, which supports the front
half 21F of the footrest 21 while biasing the front half 21F upward so
that the front half 21F can move in the vertical direction, and an
actuator 216, which supports the back half 21B of the footrest 21 movably
in the vertical direction.

[0102]The detector 61 is composed of a known means like an electromyograph
for detecting as active contractile activity of muscles electrically, a
muscle hardness meter for detecting the active contractile activity of
muscles dynamically, or a measurement equipment for detecting Oxygen
consumption depending on a muscle contraction by using near-infrared
spectroscopy. The detector 61 is configured to convert, a detection value
of the muscle activity into an electrical signal (a detection signal) and
to output the electrical signal into the controller 62. In addition, it's
preferred that the muscle activity detected by the detector 61 is at
least activity of either hamstrings as biceps femoris muscle, a
semimembranosus muscle and a semitendinosus muscle), or triceps surae
muscles gastrocnemius muscle and a soleus muscle).

[0103]The controller 62 is an electrical circuit constructed mainly from a
microcomputer, and controls the actuator 216 according to the detection
signal (a detection value of the muscle activity) received from the
detector 61, and controls the movement distance of the back half 21B.

[0104]As explained in the above background art, its important for an
auxiliary exercise equipment to contract the hamstrings (the biceps
femoris muscle, the semimembranosus muscle and the semitendinosus muscle)
and a crural muscle at the same time, and to reduce a shear force acting
on the knee joint, in order to give an effect of exercise for a
quadriceps femoris muscle while reducing a load of the knee joint. The
load is applied to the toe side larger than the heel side while the foot
joint is plantarflexed, and thereby the triceps surae muscles (the
gastronemius muscle and the soleus muscle) can be contracted and at the
same time the hamstrings being coordination muscles can also be
contracted, and thus muscles around the knee can be contracted
simultaneously. As a result, if the muscle activity of the hamstrings or
the triceps surae muscles is detected by the detector 61 and the
controller 62 controls the actuator 216 so that the detection value is
larger within a predetermined appropriate range and the back half 21B of
the footrest 21 is moved downward, muscles around the knee can be
strengthened safely and efficiently. In addition, when the detector 61
detects both the muscle activity of a quadriceps femoris muscle and the
muscle activity of the hamstrings or the triceps surae muscles and the
latter muscle activity is less than the former muscle activity, the
controller 62 may be configured to increase a downward movement distance
of the back half 21B to balance the latter muscle activity with the
former muscle activity.

[0105]Although the present invention has been described with reference to
certain preferred embodiments, numerous modifications and variations can
be made by those skilled in the art without departing from the true
spirit and scope of this invention, namely claims.